Brice G, Stone H L
Med Sci Sports Exerc. 1986 Aug;18(4):396-401.
Using chronically instrumented dogs with a healed anterior wall myocardial infarction, we have assessed the effect of acute beta-adrenergic blockade on exercise tolerance, left ventricular (LV) performance, and myocardial VO2. Mongrel dogs were instrumented with Doppler flow probes around the left circumflex coronary artery, LV pressure cells, epicardial ECG electrodes, and left atrial and coronary sinus catheters. Myocardial infarction was produced by ligation of the left anterior descending coronary artery at time of instrumentation (approximately 20% LV mass). After a 1-month recovery period, dogs were subjected to two identical submaximal graded exercise tests on a treadmill on separate days, once without (control) and once with (propranolol, 1 mg X kg-1, i.v.) acute beta-adrenergic blockade. Heart rate, LV pressure, dP/dt max, left circumflex blood flow velocity, and myocardial VO2 index were measured at each stage of the graded exercise test. All variables were significantly reduced from control during beta-block in exercise. beta-Adrenergic blockade in the presence of a 1-month-old anterior wall myocardial infarction did not compromise exercise capacity during submaximal exercise.
利用患有愈合性前壁心肌梗死的长期植入仪器的犬类，我们评估了急性β-肾上腺素能阻断对运动耐力、左心室（LV）功能和心肌耗氧量的影响。杂种犬在左旋冠状动脉周围植入多普勒血流探头、LV压力传感器、心外膜心电图电极以及左心房和冠状窦导管。在植入仪器时（约占LV质量的20%）通过结扎左前降支冠状动脉造成心肌梗死。经过1个月的恢复期后，犬类在不同日期在跑步机上进行两次相同的次最大分级运动试验，一次无（对照）急性β-肾上腺素能阻断，一次有（普萘洛尔，1 mg·kg-1，静脉注射）急性β-肾上腺素能阻断。在分级运动试验的每个阶段测量心率、LV压力、dP/dt max、左旋血流速度和心肌耗氧量指数。在运动时β-阻断期间，所有变量均较对照显著降低。在存在1个月龄前壁心肌梗死的情况下进行β-肾上腺素能阻断，在次最大运动期间不会损害运动能力。
